The present invention relates to a device for turning over piles of sheet-like material. A frame with an input and output aligns the piles according to a longitudinal conveying path of the piles. A turn-over grip, mounted to swivel around a horizontal axis extending transversely to the longitudinal direction, comprises two conveyors that are vertically juxtaposed to each other. These two conveyors sandwich the pile between them, and swivel to turn the pile upside down. One conveyor is used for delivering the piles into the device, and the other for unloading the piles after the turn-over operation has been completed. A pressing device exerts a pressure on the pile through the conveyors during the rotation. In other words, the device of the present invention receives piles of stacked sheets and selectively turns them upside down.
One-sided printed cardboard blanks are cut out with the printed side facing upwards. In the subsequent processing operations leading to a folder-gluer for processing blanks, the printed side must face downwards, which requires turning over of the blank piles. The task is extremely difficult, and more problematic when the blank""s surface is wide. The difficulty owing to the need to turn over such piles is aggravated by the fact of having to carry and convey these piles, and have a laborer assigned to the task of turn over several tons of cardboard per day.
A device for turning over piles has already been made available in the prior art. But the available devices are inconvenient and raise various issues pertaining to precision, reliability, process monitoring, the need to mark the first blanks of each pile by two series of rollers between which the pile is strongly pinched during the turning operation, the ability to handle differently sized blanks, and other issues, all of which have been responsible for the prior art devices not becoming a commercial success.
Given the processing speed reached by current folder-gluers, it is imperative to avoid the need for manual operations, particularly ones related to the turning over of the piles, not only to reduce the pain and inconvenience of the job, but also to avoid unnecessary labor, increased production costs and reduced production rates.
It is an object of the present invention to reliably solve the problem of turning over piles of sheets or sheet-like material, by creating a buffer zone allowing loading freedom for the conductor.
Essentially, in a device according to the present invention, there is provided a frame including an input and an output, that is aligned according to a longitudinal conveying path of the piles. A fold-over or turn-over grip, which swivels around a horizontal axis extending transversely to the longitudinal direction, is constituted as two conveying units that are juxtaposed to one another, with a lower one of the conveying units being deployed for delivering the piles entering the device and the other, upper conveying unit serving for removing the piles after the overall unit has been turned upside down around the horizontal axis.
A pressing unit acts on the piles by resiliently biasing one of the conveying units during the rotation, so that the pile is tightly sandwiched between the two conveying units.
The device further includes telescopic thrusts and a pusher carriage that assist in moving the pile of material between the conveying units, in order to remove the pile from between the conveyor by moving forward, or alternatively, to move the pile backwards, if needed.
The device of the invention allows and enables entirely automatic feeding of the material in the folder-gluer machine. The sole manual operation remaining is the setting or loading of the piles of cardboard sheets on a belt conveyor located upstream. This enables continuous feeding from a pre-feeder arranged between the turning over device and the folder-gluer. Overall, the device and system of the present invention facilitate attaining much faster processing rates of the folder-gluer.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.